Calcium cyanamide

Rich harvest, healthy environment

The success began with a setback. At the end of the 19th century, two chemists Dr. Adolph Frank and Dr. Nikodem Caro set out to find a way of synthesizing calcium cyanamide to produce cyanide. Cyanide plays an important role in extracting precious metals and held great sales potential at the time. The two researchers successfully achieved the synthesis they had been hoping for in 1895. However, three years later, their success proved to be deceptive.

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In 1898, one of their colleagues demonstrated that what was actually produced during the reaction at temperatures exceeding 1000 C° was not cyanide, as they had hoped, but calcium cyanamide, which later created great excitement as versatile fertilizer.

Initially, no one was aware of the revolutionary significance of this reaction. Not until three years later, in 1901, did Dr. Albert Frank, son of Adolph Frank, recognize the enormous potential of the discovery. For the first time the “erroneous” calcium cyanamide synthesis had made it possible to exploit the unlimited supplies of atmospheric nitrogen so that it could be used to fertilize fields. The industrial utilization of this process starting 1908 put an end to the practice of green manuring of fallow fields with clover, a method still widely used at that time. The result was a leap in the amount of usable field area. Moreover, the mineral fertilizer calcium cyanamide increased the yield several times over.

The agricultural supply for the populace in times of progressing industrialization was thus secured. After the substance was initially used as a nitrogen and lime fertilizer, it soon became clear that it was also effective against weeds, harmful fungi and animal pests.

Calcium cyanamide was therefore recognized as not only a fertilizer, but also a plant protection agent, which, at a time when all weed control was done mechanically, represented a great step forward. Consequently, it is hardly surprising that the output of calcium cyanamide rapidly grew enormously. In 1910, 30,000 tons were produced; in 1928, global production reached an astonishing 1,2 million tons.

Development of calcium cyanamide also led to the founding of the Bayerische Stickstoff-Werke AG in Trostberg in 1908. In 1939, this became the Süddeutsche Kalkstickstoffwerke AG (SKW Trostberg), one of the predecessor companies of today’s Evonik group.

Calcium Cyanamide packing in the 1930ies

Today, calcium cyanamide is available on the market from the Trostberg site in two forms: ground, which is finely powdered, and granulated (PERLKA).

After a temporary decline, demand has again risen in recent years owing to the ban on several pesticides which have lost their licenses due to the environmental damage they cause. Consequently, agriculture is once again putting its trust in calcium cyanamide. Even after around 100 years of use, no harmful long-term effects to the earth or environment have been observed, nor have weeds or pests developed a resistance to it.